Question

Why does lime water turn milky when carbon dioxide is passed through it?Why does its milkiness disappear when excess of carbon dioxide is passed through it?Explain with a chemical reaction.

Answer 1

Lime water turns milky due to marble chips and NaOH

Answer 2

lime water is calcium oxide . so when we pass the carbon dioxide it reacts with lime water as follow

 CaO  + CO2 -------}  CaCO3    which is white in colour